Modified acacia and use thereof

ABSTRACT

The present invention aims to provide modified gum arabic having an increased total dietary fiber content and use thereof. The modified gum arabic of the present invention, which is obtained by heating gum arabic, has a total dietary fiber content (determined by AOAC method) of not less than 90%, and preferably has a weight-average molecular weight of not less than 1,000,000. This modified gum Arabic is usable as a dietary fiber material or an additive for enriching dietary fiber to be used in foods, drinks and medicines. Therefore, the present invention provides foods, drinks or medicines containing the above-described modified gum Arabic as dietary fiber material or an additive for enriching dietary fiber.

TECHNICAL FIELD

The present invention relates to modified gum arabic. In particular, theinvention relates to gum arabic modified so as to contain a high totaldietary fiber content.

BACKGROUND OF THE INVENTION

Gum arabic is a natural resin prepared by drying the rubbery exudatefrom the trunks and branches of plants that belong to the genus Acaciaof the Leguminasae family, in particular, Acacia senegal and Acaciaseyal. Gum arabic is highly soluble in water and its aqueous solutionprovides high emulsion stability, protective colloidability, andfilmforming ability even at low concentrations, and therefore has beenwidely used as an emulsifier, thickener, stabilizer, and coating agent(“Industrial Gums, Polysaccharides and their Derivatives”, secondedition, Academic Press, New York and London, 1973, pp 197-263).Furthermore, gum arabic contains dietary fiber that is not digested byhuman digestive enzymes. The content of dietary fiber in gum arabicmeasured by enzymatic-HPLC methods is 80 to 90% (Monthly Food Chemical,2002-6, pp 85-89), 85% measured by the AOAC method, and not less than70% measured by the Englyst method (Monthly Food Chemical, 1997-7, pp102-104).

In recent years, many researchers have indicated that an insufficientdietary fiber intake caused by a westernized Japanese diet is relevantto the increase in patients suffering from diabetes, obesity,arteriosclerosis and the like lifestyle-induced diseases. Therefore, thephysiological functions of dietary fiber are attracting attention, andthe necessity of intaking dietary fiber is highlighted.

As described above, because gum arabic has a significantly lowerviscosity than macromolecular polysaccharides, which are a differentkind of dietary fiber, gum arabic can be used at high concentrations andhas a high level of safety. Gum arabic can be added to foods, includingdrinks, without adversely affecting their texture, and therefore gumarabic is a useful material for intaking a large amount of dietaryfiber. Accordingly, there is a demand for developing foods that containgum arabic as dietary fiber.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide gum arabic (modifiedgum arabic) that is modified so as to contain a large amount of dietaryfiber, in particular total dietary fiber, with aiming to develop foods,drinks and medicines in which gum arabic is used as dietary fiber.Another object of the present invention to provide foods and drinksusing such modified gum arabic as a dietary fiber material.

In order to distinguish gum arabic used as a material for modificationfrom the modified gum arabic of the present invention, such gum arabicfor modification is referred to as “gum arabic”, “natural gum arabic” or“unmodified gum arabic” in this specification.

In order to solve the above problems, the present inventors conductedintensive research and found that the total dietary fiber content can beincreased by heating natural gum arabic (Acacia senegal or Acacia seyal)under specific conditions.

The present invention has been accomplished based on that finding andencompasses the following aspects.

Item 1. Water-soluble modified gum arabic having a total dietary fibercontent (measured by the AOAC method) of not less than 90%.

Item 2. Modified gum arabic according to Item 1, which has theweight-average molecular weight of not less than 1 million.

Item 3. Modified gum arabic according to Item 1 or 2, which is used as adietary fiber material for a food, drink, or medicine.

Item 4. Modified gum arabic according to Item 1 or 2, which is used asan additive for enriching dietary fiber of a food, drink, or medicine.

Item 5. Modified gum arabic according to any one of Items 1 to 4, whichis obtained by heating gum arabic.

Item 6. Modified gum arabic according to Item 5, which is obtained byheating gum arabic at 110° C. for not less than 24 hours, or underconditions by which similar effects can be obtained.

Item 7. Modified gum arabic according to any one of Items 1 to 6, whichis of Acacia senegal origin.

Item 8. A method for preparing the modified gum arabic of any one ofItems 1 to 6, which comprises a step of heating gum arabic at 110° C.for not less than 24 hours, or under conditions by which similar effectscan be obtained.

Item 9. A dietary fiber material for a food, drink, or medicine(preferably, an oral medicine), the dietary fiber material comprising orconsisting of the modified gum arabic of any one of Items 1 to 7.

Item 10. A method in which the modified gum arabic of any one of Items 1to 7 is used as a dietary fiber material for a food, drink, or medicine(preferably, an oral medicine).

Item 11. An additive for enriching the dietary fiber in a food, drink,or medicine (preferably, an oral medicine), the additive comprising orconsisting of the modified gum arabic of any one of Items 1 to 7.

Item 12. A method in which the modified gum arabic of any one of Items 1to 7 is used as an additive for enriching the dietary fiber of a food,drink, or medicine (preferably, an oral medicine).

Item 13. A food, drink, or medicine (preferably, an oral medicine)containing the modified gum arabic of any one of Items 1 to 7 as adietary fiber material.

Item 14. A food or drink whose dietary fiber content is increased bycontaining the modified gum arabic of any one of Items 1 to 7 as adietary fiber material.

Item 15. The food, drink, or medicine (preferably, an oral medicine)according to Item 13 or 14, which is used for improving bowel movements,improving intestinal functions, improving intestinal conditions,preventing obesity, controlling blood lipid levels, reducing bloodcholesterol levels, controlling blood-sugar levels or preventing thedevelopment of cancer.

Item 16. A method for increasing the dietary fiber content of a food ordrink by using the modified gum arabic of any one of Items 1 to 7 as adietary fiber material in preparing the food or drink.

Item 17. Use of the modified gum arabic of any one of Items 1 to 7 as adietary fiber material.

Item 18. Use of the modified gum arabic of any one of Items 1 to 7 as anadditive for enriching dietary fiber.

Item 19. Use of the modified gum arabic of any one of Items 1 to 7 inpreparing a food, drink, or medicine (preferably, an oral medicine).

Item 20. The use of the modified gum arabic according to Item 19,wherein the food, drink, or medicine is used for improving bowelmovements, improving intestinal functions, improving intestinalconditions, preventing obesity, controlling blood lipid levels, reducingblood cholesterol levels, controlling blood-sugar levels, or preventingthe development of cancer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a chromatogram obtained by subjecting modified gum arabicto GPC-MALLS (gel filtration chromatography), wherein the modified gumarabic was prepared by placing 70 kg of cracked unmodified gum arabic(A. senegal, particle size of 5 mm, weight-average molecular weight of5.36±0.02×10⁵) in a 100 L stainless steel drum, and heating it in anoven at 110° C. for 36 hours.

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Modified Gum Arabic

The modified gum arabic of the present invention has a total dietaryfiber content (measured by the AOAC method) of not less than 90% per 100weight % of modified gum arabic.

Total dietary fiber means indigestible polysaccharides and lignin whichare not hydrolyzed by human digestive enzymes when consumed. The totaldietary fiber content in the modified gum arabic of the presentinvention can be determined by the Prosky method (AOAC Official Method:CEREAL FOODS CHAPER 32 (2000), p. 7-12, “AOAC OFFICIAL METHODS OFANALYSIS”, AOAC official method 991.43), which is a method forquantifying dietary fiber.

The Prosky method is a method for determining the quantity of totaldietary fiber (including water-soluble dietary fiber and insolubledietary fiber) in a sample. The specific method for determining thetotal dietary fiber content of a sample is as follows: 1 g of sample(solid) is treated stepwise with heat resistant a-amylase, protease andamyloglucosidase, and starch and proteins thereof are hydrolyzed.Water-soluble dietary fiber and insoluble dietary fiber are collectivelyprecipitated by adding a 4 times amount of ethanol to the reactionmixture. The precipitate is filtered to collect a residue. The collectedresidue is washed with ethanol and acetone, dried, and the weightthereof (weight of the dried residue) is measured. The total dietaryfiber content in the sample is obtained by subtracting the weight ofindigestible protein and ash from the weight of the dried residue.

As a simple method, the total dietary fiber content of a sample(modified gum arabic in the case of the present invention) can bemeasured by using, for example, a “total dietary fiber content assaykit” (product of Biocon (Japan) Ltd.).

The modified gum arabic of the present invention has a total dietaryfiber content of not less than 90 weight %, preferably not less than 91weight %, and more preferably not less than 93 weight %. There is noupper limit thereof up to 100 weight % as long as the modified gumarabic is water-soluble as a whole. There is no limit to the percentageof insoluble dietary fiber in the total dietary fiber content as long asthe modified gum arabic is water-soluble as a whole.

“Water-soluble” in this specification means that a sample can be almostcompletely dissolved in an excess of water, without restriction to thetype of water, e.g., ion-exchanged water or ion-containing water, or towater temperature, as long as the gum arabic is soluble.Hydro-gelatinous gum arabic cannot be dissolved in water even if a largeamount of water is added or by heating, and therefore the term“water-soluble” is used in the present specification to distinguish themodified gum arabic of the invention from hydro-gelatinous gum arabic,which is insoluble in water. In other words, the modified gum arabic ofthe invention does not include modified polymeric gum arabic that isinsoluble in water, such as hydrogels, etc.

Moreover, it is preferable that the modified gum arabic of the presentinvention have the foresaid total dietary fiber content, bewater-soluble, and be the same as or similar to unmodified gum arabic interms of immunological reactivity. The phrase “the same as or similar tounmodified gum arabic in terms of immunological reactivity” means thatthe difference between the degree of immunological inhibition of themodified gum arabic and that of unmodified gum arabic is within ±10%, asmeasured by indirect competitive ELISA using a quantifiable antibody(e.g., SYCC7) [Thurston, M. I. et al., Detection of gum from Acaciaseyal and species of combretum in mixtures with A. senegal usingmonoclonal antibodies, Food & Agric. Immunol., 10: 237-241(1998);Thurston, M. I. et al., Effect of heat and pH on carbohydrate epitopesfrom Acacia senegal by specific monoclonal antibodies, Food & Agric.Immunol., 11: 145-153(1999)].

The form of the modified gum arabic of the present invention is notlimited and it can take any form, including blocks, beads, coarsepulverizates, granules, pellets and powders.

The modified gum arabic of the present invention can be prepared byheating gum arabic from Acacia senegal or Acacia seyal using athermostat or a heater, such as an oven, for example, at 110° C. for notless than 24 hours.

The unmodified gum arabic used as a raw material (hereunder theunmodified gum arabic may be referred to as unmodified gum arabic (A.senegal), unmodified gum arabic (A. seyal), or collectively unmodifiedgum arabic) is a natural resin (polysaccharide) prepared by drying arubbery exudate obtained from the trunks and branches of Acacia senegalor Acacia seyal of the genus Acacia, family Leguminasae, or any othertree belonging to the same genus. It is also possible to use unmodifiedgum arabic that has been subjected to treatments, such as purification,desalting, pulverization, spray drying, etc.

Unmodified gum arabic is produced in countries of North and West Africafrom Ethiopia to Senegal (Ethiopia, Sudan, Senegal, Nigeria, Niger, andGhana), countries of East Africa such as Kenya and Uganda, the Sahararegion of Africa and the basins of the tributaries of the Nile.Unmodified gum arabic produced in any of the above areas can be used inthe present invention regardless of its origin.

Furthermore, unmodified gum arabic is not particularly restricted in itswater content. Commercially available unmodified gum arabic undergoes areduction in water content when dried by heating at 105° C. for 6 hours(loss-on-drying) of generally not more than 40 weight %, preferably notmore than 30 weight %, and more preferably not more than 20 weight %. Inthe present invention, unmodified gum arabic having such water contents(loss-on-drying) can be used without limitation.

Unmodified gum arabic can usually be available in the forms of blocks,beads, coarse pulverizates, granules, pellets, and powders (includingspray dried powders and roller dried powders). However, in the presentinvention, unmodified gum arabic of any form can be used withoutlimitation as a material to be processed. It is possible to use gumarabic powder (spray dried or roller dried) having an average particlediameter of several tens μm to several hundred μm. There is noparticular upper limit to the average particle diameter but from theviewpoint of modification efficiency, the average particle diameter ispreferably not more than 100 mm. The average particle diameter ispreferably in the range of from 1 mm to 100 mm and more preferably from2 mm to 50 mm.

Examples of methods for heating unmodified gum arabic include heatingunmodified gum arabic at 110° C. for more than 24 hours using an oven(thermostat or heater). A preferable heat treatment is such thatunmodified gum arabic is heated at 110° C. for not less than 48 hours.Depending on the type of the unmodified gum arabic (A. senegal or A.seyal) to be subjected to heat treatment, the upper limit to theduration of heating when heated at 110° C. is usually about 72 hours.The above heating temperature and duration of heating are only examplesof methods (conditions) for preparing modified gum arabic of the presentinvention, and therefore these conditions serve as a guideline forpreparing the modified gum arabic of the present invention, and not tolimit the modified gum arabic of the present invention.

In other words, as long as water-soluble modified gum arabic having thetotal dietary fiber content specified in the present specification canbe obtained, the heating method is not limited to the above examples andheating temperature, duration of heating, heating means, and heatingconditions (relative humidity, with or without being a closed system)can be selected as desired. The effects of the present inventionachieved by a heat treatment conducted under the conditions describedabove can also be obtained by a method wherein unmodified gum arabic isheated at a temperature lower than 110° C. for more than 24 hours or ata temperature higher than 110° C. for a shorter time. Specifically, amethod wherein the unmodified gum arabic is heated at 80° C. for 3 daysto 2 weeks or longer may be mentioned as one example of the former case.When the unmodified gum arabic is heated using microwave radiationinstead of an oven, the same effects can be achieved in less time. Inaddition, a heat treatment in the absence of oxygen, such as undernitrogen displacement conditions, is advantageous because it can preventdiscoloration of the gum arabic.

Furthermore, when gum arabic belonging to the Acacia senegal species isused as a material for the modified gum arabic of the present invention,it is preferable that such unmodified gum arabic have a weight averagemolecular weight of not less than 1×10⁶.

The weight average molecular weight is determined by the use of gelpermeation chromatography wherein three detectors, i.e., a multi anglelaser light scattering (MALLS) detector, a refractive index (RI)detector and an ultraviolet (UV) detector are coupled by on-line. (Inthe present specification, such gel permeation chromatography isreferred to as “GPC-MALLS”.) According to GPC-MALLS, the molecularweight is measured by the MALLS detector, the weight of each component(composition ratio) is measured by the RI detector, and protein contentis measured by the UV detector. Therefore, it is possible to obtain themolecular weight and the composition of the analyzed components withoutreference to a standard gum arabic of known molecular weight. Fordetailed principals and characteristics of GPC-MALLS, see Idris, O. H.M., Williams, P. A. Phillips, G. O.; Food Hydrocolloids, 12, (1998) pp.375-388.

Conditions for GPC-MALLS employed in the present invention are as below:

-   Column: Superose (6 HR) 10/30 (Pharmacia Biotech, Sweden)-   Flow rate: 0.5 mL/minute-   Eluant: 0.2 M NaCl-   Preparation of sample: The sample to be analyzed is diluted with the    eluant (0.2 M NaCl).-   Sample concentration: 0.4% (W/V)-   Injection volume of sample solution: 100 μl-   dn/dc: 0.141-   Temperature: Room temperature-   Detector: 1. MALLS (multi angle laser light scattering) detector:    DAWN DSP (manufactured by Wyatt Technology Inc., USA)    -   2. RI detector    -   3. UV detector    -   (absorption at 214 nm)

By processing the data obtained by the GPC-MALLS conducted under theabove-described conditions using software, i.e., ASTRA Version 4.5(Wyatt Technology), parameters of the gum arabic such as the weightaverage molecular weight, recovery ratio (% mass), polydispersity value(P), and root mean square radius of gyration (Rg) can be obtained. Whenthe data is processed considering all of the peaks on the chromatogramobtained using an RI detector as one peak, the obtained molecular weightis identified as the weight average molecular weight (M_(wt)) of thepresent invention (specifically, “M_(wt) processed as one peak”). Whenthe point where the RI plot begins to rise from the baseline of thechromatogram is defined as the “starting point”, and the point where theRI chart falls and touches the baseline is defined as the “endingpoint”, the aforementioned one peak of the chromatogram means the areafrom the starting point to the ending point.

For example, FIG. 1 shows a chromatogram obtained by subjecting modifiedgum arabic to GPC-MALLS (gel filtration chromatography), wherein themodified gum arabic was prepared by placing 70 kg of cracked unmodifiedgum arabic (A. senegal, particle size of 5 mm, weight-average molecularweight of 5.36±0.02×10⁵) in a 100 L stainless steel drum, and heating itin an oven at 110° C. for 36 hours. The horizontal axis, “Volume (mL)”,indicates the cumulative volume of the eluant passing through the columnand the vertical axis, ‘AUX, 90° Detector’, indicates the relativeintensity at each detector (MALLS detector, RI detector, and UVdetector). The chromatogram (MALLS chart) obtained by the MALLS detectorindicates the light scattering intensity at 90°, which is dependent onthe molecular weight distribution. The RI chromatogram (RI chart)obtained with the RI detector indicates the refractive index intensity,which correlates with the weight of the component(s) contained in theeluant. The chromatogram obtained by the UV detector shows the UVabsorption at 214 nm, which correlates with the protein distribution.

When the data is processed considering all the peaks on the chromatogramobtained using an RI detector as one peak, the obtained molecular weightis identified as the weight average molecular weight (M_(wt)) of thepresent invention (specifically, “M_(wt) processed as one peak”). Whenthe point where the RI chart begins to rise from the baseline of thechromatogram is defined as the “starting point”, and the point where theRI chart falls and touches the baseline is defined as the “endingpoint”, the aforementioned one peak on the chromatogram means the areafrom the starting point to the ending point.

There is no limitation to the weight average molecular weight of themodified gum arabic of the present invention as long as it is not lessthan 1 million; preferably it is not less than 1.2 million, morepreferably not less than 1.5 million, and still more preferably not lessthan 2 million. There is no specific upper limit to the weight averagemolecular weight as long as the modified gum arabic has total dietaryfiber content of not less than 90 weight % and is soluble in water;however, it is preferably 2.5 million or less.

(2) Dietary Fiber Material/an Additive for Enriching Dietary Fiber

The present invention provides use of the above-descried modified gumarabic having a total dietary fiber content of not less than 90 weight %measured by the AOAC official method as a material for foods, drinks andmedicines. The modified gum arabic can be used for enhancing dietaryfiber (increasing the dietary fiber content) in foods, drinks, andmedicines. Specifically, the present invention provides an edibleadditive that can be orally taken for enhancing dietary fiber(increasing the dietary fiber content) in foods, drinks, and oralmedicines. In the present invention, such an edible additive is adietary fiber material or an additive for enriching dietary fiber infoods, drinks, and medicines.

The dietary fiber material or additive for enriching dietary fiber ofthe present invention may consist solely of the modified gum arabic ofthe present invention, or comprise the modified gum arabic of thepresent invention as an active ingredient together with otherwater-soluble dietary fibers, insoluble dietary fibers, and/or foodhygienically and pharmaceutically acceptable carriers or additives. Inthe latter case, it is preferable that the content of the modified gumarabic of the present invention be not less than 30 weight %.

Examples of water-soluble dietary fibers other than modified gum arabicare pectin, guar gum, psyllium, galactomannan, xyloglucan, locust beangum, glucomannan, sodium alginate, chondroitin sulfate, lowmolecular-alginic acid, low molecular-guar gum, indigestible dextrin,polydextrose, pullulan, fiberon, etc.

Examples of insoluble dietary fibers are cellulose, wheat bran, applefiber, sweet potato fiber, cone fiber, chitin, etc.

There is no limitation on the usable food hygienically andpharmaceutically acceptable carriers and additives, and examples thereofinclude dextrin, lactose, maltose, trehalose, glucose and likesaccharides; sorbitol, mannitol and like sugar-alcohols; and glycerol,propylene glycol and like polyhydric alcohols.

The dietary fiber material or additive for enriching dietary fiber isadded with other materials as an ingredient in a process for preparing afood, drink or oral medicine to increase the dietary fiber contentthereof.

(3) Foods and Drinks and/or Medicines

The present invention provides foods, drinks and medicines having anincreased dietary fiber content by adding the modified gum arabic havinga total dietary fiber content of not less than 90 weight % measured bythe AOAC official method. Such foods, drinks and medicines can also beprepared by using the dietary fiber material or additive for enrichingdietary fiber of the present invention instead of the above-describedmodified gum arabic.

There is no restriction on the types, content of modified gum arabic,and total dietary fiber content of the foods and drinks of the presentinvention as long as the total dietary fiber content is increased bycontaining the modified gum arabic of the present invention.

The content of modified gum arabic of the present invention ispreferably not less than 1 weight %, more preferably not less than 5weight %, and further more preferably not less than 10%. There is noparticular upper limit of the content. However, considering the factthat the modified gum arabic of the present invention itself can be used(eaten) as health food (functional food), the upper limit thereof is 100weight %.

The foods and drinks of the present invention are not limited andexamples thereof include soft drinks, fruit drinks, milk beverages,lactic acid bacteria beverages, carbonated beverages, vegetable drinks,sports drinks, black tea beverages, green tea beverages, powderbeverages, coffee beverages, cocoa beverages, soups, siruko (adzuki-beansoup with rice cake) and like beverages; puddings, jellies, yogurts andlike desserts; ice creams, popsicles and like cold sweets; chewing gum,chocolate, soft candies, biscuits, cookies and like confectioneries;dressings, sauces, ketchup and like seasonings; and jams, noodles, fishcakes, syrups, breads, ready-made meals and like processed foods. Themodified gum arabic of the present invention can also be provided assupplements (health foods, functional foods) in the form of tablets,capsules, pills, granules, pulvis, powders, solutions (ampuled liquidmedicines).

When the foods and drinks of the present invention are provided in theform of supplements, in addition to an effective amount (the amounteffective for increasing dietary fiber) of the modified gum arabic ofthe present invention, which serves as an active ingredient, foodhygienically acceptable carriers or other additives may be added.

The amount of modified gum arabic contained in the foods or drinks andthe dosage thereof are not limited and can be suitably selecteddepending on the type of the food or drink, intended effects and thedegree thereof, and other conditions. The dosage varies depends on thetype of the food or drink, but a preferable dosage is about 1 to 100 gper day for an adult with a body weight of 60 kg as calculated by theamount of modified gum arabic.

By containing a large amount of dietary fiber, the foods and drinks ofthe present invention have various physiological functions or diseaseprevention effects such as reducing blood cholesterol levels,controlling blood lipid levels, improving bowel movements (includingrelieving constipation), improving intestinal functions by improving theintestinal conditions, preventing obesity, controlling blood-sugarlevels, preventing the development of cancer, etc. Furthermore, sincethe modified gum arabic has a low viscosity, it does not adversaryaffect the texture of the foods or drinks of the present invention evenwhen a large amount of the modified gum arabic is included, and it doesnot cause any side effects such as diarrhea when a large amount thereofis consumed.

By containing the modified gum arabic of the present invention, themedicines encompassed in the present invention have physiologicalfunctions or disease prevention effects such as reducing bloodcholesterol levels, controlling blood lipid levels, improving bowelmovements (including alleviating constipation), improving intestinalfunctions by improving the intestinal conditions, preventing obesity,controlling blood-sugar levels, preventing the development of cancer,etc. There is no limitation on the content of the modified gum arabicand the total dietary fiber content as long as the medicines of thepresent invention have such a function or effect. The medicinesencompassed in the present invention are oral medicines. Such medicinescan be mixed, formed, or prepared as tablets, pills, pulvis, powders,granules, capsules, dry syrups or the like solid solids; or assolutions, suspensions, emulsions, syrup or the like liquids.

A medicine of the present invention may contain pharmacologicallyacceptable carriers or additives together with modified gum arabic.Examples of carriers used in preparing such medicines includeexcipients, diluting agents, binders, humectants, disintegrators,disintegration inhibitors, absorption accelerators, lubricants,solubilizers, buffers, emulsifiers, and suspensions, i.e., carrierstypically used depending on the dosage form of the preparation. Examplesof usable additives include stabilizers, preservatives, buffers,isotonicity agents, chelating agents, pH adjustors, surfactants,coloring agents, perfumes, flavors, sweetening agents, etc., i.e.,additives typically used depending on the dosage form of thepreparation.

The amount of modified gum arabic contained in the medicine of thepresent invention varies depending on the form of the medicine and theadministration route thereof and cannot be generally be specified, butis preferably not less than 5 weight % of the final pharmaceuticalpreparation, and more preferably not less than 10 weight %. There is noupper limit of the content thereof, but in the light of the fact thatthe modified gum arabic of the present invention itself can be used as amedicine, the upper limit is 100 weight %.

The dosage of the medicine of the present invention is not limited andcan be suitably selected depending on the intended effects, duration ofadministration, administration method, duration of treatment, patient'sage and sex, and other conditions. The dosage varies depending on theadministration route, but can be suitably selected from the range about1 to 100 g per day for an adult with a body weight of 60 kg ascalculated by the amount of a pharmaceutically effective ingredient.

EXAMPLES

The details of the present invention are explained below with referenceto Examples. However, the present invention is not limited to or bythese Examples. In the Examples, unless otherwise specified, “parts”means “parts by weight” and “%” means “weight %”.

Experimental Example 1

(1) Preparation of Modified Gum Arabic

One kg of cracked gum arabic belonging to the Acacia senegal species(unmodified gum arabic from A. senegal: ‘Sample 1’, particle size of 5mm) was placed in an unsealed stainless steel container, and heated at110° C. for 24 hours or 48 hours using an oven (gum arabic samplesheated for 24 hours and 48 hours are referred to as ‘Sample 1/24’ and‘Sample 1/48’, respectively).

(2) Content of Dietary Fiber

The total dietary fiber contents of the above-obtained gum arabicsamples (Sample 1, Sample 1/24, Sample 1/48) were measured by the Prosky(AOAC) method.

Specifically, total dietary fiber contents of two specimens per sampleeach containing 1 g gum were measured according to the followingprocedure. Note that one of the two specimens was for measuring thecontent of indigestible proteins and the other was for measuring the ashcontent:

1. Two specimens each containing 1.0 g were weighed to 0.1 mg precisionand each specimen was placed in a 400 mL beaker.

2. To 1.0 g of each specimen were added 50 mL of 0.08 M phosphate buffer(pH 6.0) and 0.1 mL of heat resistant a amylase (manufactured by Novo,termamyl 120 L). The top of the beaker was covered with aluminum foil,the beaker was shaken every 5 minutes in a boiling-water bath, and themixture was reacted for 30 minutes after the temperature of the contentof the beaker reached 95° C.

3. The temperature of the content of the beaker was reduced to roomtemperature, 10 mL of 0.275 N sodium hydroxide solution was added, andthe mixture was adjusted to pH 7.5±0.2. A protease solution (0.1 mL, asolution obtained by dissolving protease (manufactured by Sigma, productname of P3910) in a 0.08 M phosphate buffer (pH6.0) so that the contentthereof was 50 mg/mL) was added to the mixture, the top of the beakerwas covered with aluminum foil, the beaker was shaken in a water bath at60° C., and the mixture was reacted for 30 minutes after the temperatureat the center of the mixture reached 60° C.

4. When the temperature of the mixture was reduced to room temperature,10 mL of 0.325 M aqueous hydrochloric acid was added, and the mixturewas adjusted to pH 4.0 to 4.6. To the mixture was added 0.3 mL ofamyloglucosidase solution (amyloglucosidase, manufactured by Sigma,product name of P-9913), the top of the beaker was covered with aluminumfoil, the beaker was shaken in a water bath at 60° C., and the mixturewas reacted for 30 minutes after the temperature at the center of themixture reached 60° C.

5. 280 mL of 95% aqueous ethanol that had been measured and heated to60° C. in advance was added to the enzyme reaction solution in thebeaker, and the beaker was allowed to stand under room temperature forexactly 60 minutes, obtaining a precipitate.

6. Using a wash bottle, 78 v/v % aqueous ethanol was poured into a glassfilter accommodating celite (celite 545, manufactured by Sigma, C-8656)to suspend the celite. The suspension was subjected to vacuum suction toform a uniform mat-shaped filter layer. The enzyme reaction solutioncontaining the precipitate generated by ethanol was poured onto thefilter and subjected to suction filtration. The residue was sequentiallywashed with 20 mL of 78 v/v % aqueous ethanol three times, with 10 mL of95 v/v % aqueous ethanol twice, and with 10 mL of acetone twice.

7. The filter containing the residue was dried over night in a vacuumoven (70° C.), cooled in a desiccator, weighed to 0.1 mg precision, andthe actual amount of the residue was obtained by subtracting the weightof the filter and celite therefrom.

8. The residue of one of the two specimens was scraped off together withcelite. The nitrogen content of the residue was determined by asemimicro-Kjeldahl method, and the protein content thereof was obtainedby multiplying by a conversion factor of 6.25. The other residue wassubjected to ashing at 525° C. for 5 hours, cooled in a desiccator,weighed to 0.1 mg precision, and the ash content in the residue wasobtained.

9. The blank residue, blank protein, and blank ash weights were obtainedby conducting steps 2 to 8 in the absence of a sample.

The total dietary fiber content % was calculated using the obtainedweights by the following formulae.${{Total}\quad{dietary}\quad{fiber}\quad{content}\quad\%} = {\frac{\begin{matrix}{{{Residue}\quad{mg}} - \left\{ {\left\lbrack \frac{{{Protein}\quad{residue}\quad\%} + {{Ash}\quad{residue}\quad\%}}{100} \right\rbrack \times} \right.} \\{\left. {{Residue}\quad{mg}} \right\} - {Blank}}\end{matrix}}{{Sample}\quad{mg}} \times 100}$${{Protein}\quad{residue}\quad\%} = {\left\lbrack \frac{{Protein}\quad{residue}\quad{mg}}{{Residue}\quad{mg}} \right\rbrack \times 100}$${{Ash}\quad{residue}\quad\%} = {\left\lbrack \frac{{Ash}\quad{residue}\quad{mg}}{{Residue}\quad{mg}} \right\rbrack \times 100}$${Blank} = {{{Blank}\quad{residue}\quad{mg}} - \left\{ {\left\lbrack \frac{{{Blank}\quad{protein}\quad\%} + {{Blank}\quad{ash}\quad\%}}{100} \right\rbrack \times {Blank}\quad{residue}\quad{mg}} \right\}}$${{Blank}\quad{protein}\quad\%} = {\left\lbrack \frac{{Blank}\quad{protein}\quad{mg}}{{Blank}\quad{residue}\quad{mg}} \right\rbrack \times 100}$${{Blank}\quad{ash}\quad\%} = {\left\lbrack \frac{{Blank}\quad{ash}\quad{mg}}{{Blank}\quad{residue}\quad{mg}} \right\rbrack \times 100}$(3) Measurement of Weight-Average Molecular Weight

The gum arabic samples (Sample 1, Sample 1/24, Sample 1/48) weresubjected to gel filtration chromatography employing the GPC-MALLS(Multi Angle Laser Light Scattering) method under the below specifiedconditions, obtaining chromatograms.

-   Column: Superose (6 HR) 10/30 (Pharmacia Biotech)-   Flow rate: 0.5 mL/minute-   Eluant: 0.2 M NaCl-   Preparation of sample: The sample to be analyzed was diluted with    the eluant (0.2 M NaCl).-   Sample concentration: 0.4% (W/V)-   Injection volume of sample solution: 100 μl-   dn/dc: 0.141-   Temperature: Room temperature-   Detector: 1. MALLS (multi angle laser light scattering) detector:    DAWN DSP (manufactured by Wyatt Technology Inc.)    -   2. RI detector    -   3. UV detector (absorption at 214 nm)

By processing the data obtained by the GPC-MALLS conducted under theabove-described conditions using software, i.e., ASTRA Version 4.5(Wyatt Technology), weight-average molecular weight (M_(wt) processed asone peak) was obtained. When the data is processed considering the allthe peaks on the chromatogram obtained using an RI detector as one peak,the obtained molecular weight is identified as the weight averagemolecular weight (M<) of the present invention (specifically, “M_(wt)processed as one peak”). When the point where the RI plot begins to risefrom the baseline of the chromatogram is defined as the “startingpoint”, and the point where the RI chart falls and touches the baselineis defined as the “ending point”, the aforementioned one peak of thechromatogram means the area from the starting point to the ending point.

Table 1 shows the total dietary fiber contents and weight-averagemolecular weights (M_(wt) processed as one peak) of the gum arabicsamples (Sample 1, Sample 1/24, and Sample 1/48). TABLE 1 Increase inTotal Increase in Weight- weight- dietary total average average fiberdietary molecular molecular content fiber Sample weight weight (%)(AOAC)% content (%) Sample 1 5.15 ± 0.18 × 10⁵ 100 84.0 100 Sample 1/241.15 ± 0.21 × 10⁶ 223.3 90.0 107.1 Sample 1/48 1.91 ± 0.17 × 10⁶ 370.891.0 108.3

As is clear from the results, the total dietary fiber contents in themodified gum arabic of the present invention of Samples 1/24 and 1/48increased by 7.1 weight % (107.1%-100%=7.1%) and 8.3 weight %(108.3%-100%=7.1%) respectively from the total dietary fiber content(100 weight %) of the unmodified gum arabic (Sample 1). Furthermore, theweight-average molecular weights (M_(wt) processed as one peak) wereincreased by 123.3% (223.3%-100%=123.3%) and 270.8% (370.8%-100%=270.8%)respectively.

Experimental Example 2 Immunoreaction of Modified Gum Arabic

Immunoreactivities of the gum arabic samples derived from A. senegal(Sample 1, Sample 1/24, and Sample 1/48) obtained in ExperimentalExample 1 were evaluated. More specifically, immunoreactivities of thegum arabic samples were measured using plates immobilized with one ofeach kind of gum arabic sample (concentrations: 0.005 mg/mL, 0.01 mg/mL,0.05 mg/mL, 0.1 mg/mL, 0.5 mg/mL, 1 mg/mL, and 5 mg/mL) by indirectcompetitive ELISA according to Thurston, M. I. et al. [Thurston, M. I.,et al.; Detection of gum from Acacia seyal and species of combretum inmixtures with A. senegal using monoclonal antibodies, Food & Agric.Immunol., 10:237-241 (1998); Thurston, M. I., et al., Effect of heat andpH on carbohydrate epitopes from Acacia senegal by specific monoclonalantibodies, Food & Agric. Immunol., 11:145-153 (1999)].

Before conducting the ELISA, monoclonal antibodies having no specificityand showing quantitative cross-reactivity to any species of gum arabicwere prepared. More specifically, an adjuvant was added to a salinesolution containing 1 mg/mL of gum arabic from Acacia senegal to preparean immunogen. Balb/c mice were given intraperitoneal injections of theimmunogen three times at 2-week intervals. The splenocytes of the micewith highly raised antibody titers were extracted and fused with myelomacells in polyethylene glycol. After incubating the obtained cells on anincubation plate for 10 days, the hybridoma cells were selected based onspecificity to antibodies produced in the supernatant of theproliferated hybridoma cells. The selected hybridoma cells wereincubated for another 10 days on the incubation plate and specifichybridoma cells were selected by the same procedure. Those hybridomacells producing only antibodies having the above specificity (suchantibodies were named SYCC7) were finally selected.

The ELISA was conducted using the thus-prepared SYCC7 antibody by thefollowing steps.

1. 1 mg/mL and 5 mg/mL of solutions of the three samples (Sample 1,Sample 1/24, and Sample 1/48) were diluted to 10-fold, 100-fold and1000-fold.

2. 200 μl each of the above-obtained solutions was added into wells of aplastic plate, and immobilized at 4° C. for 1 hour. The wells werewashed with saline solution, blocked with 0.3% casein-containing salinesolution and washed with 0.05% Tween 20-containing saline solution.

3. Culture supernatant of the prepared hybridoma cells was added andimmobiized for 1 hour. After washing as per the above-mentionedprocedure, the wells were subsequently immobilized withperoxidase-labeled goat anti-mouse antibodies (SIGMA, diluted 1,000-foldwith saline solution) for 1 hour.

4. After washing, tetramethylbenzidine was added as a substrate to thewells and the color intensity was measured as UV absorption at 450 nm(UV_(450nm)).

The inhibition ratio (%) for each sample at various concentrations wasdetermined by comparison with the UV absorption at 450 nm (UV_(450nm))of natural gum arabic (unmodified gum arabic: Sample 1) from A. seyal,which is defined as 100% inhibition.

Test results show that the modified gum arabic of the present invention(Sample 1/24 and Sample 1/48) and natural gum arabic (Sample 1) have thesame or similar immunological reactivities since differences in theimmunological inhibition ratio therebetween were within +10% over thetested concentration range, and therefore negligible.

Experimental Example 3

Using gum arabic (sample 1) and modified gum arabic (sample 1/24 andsample 1/48), aqueous solutions of various concentrations were preparedand the viscosities thereof were measured. Specifically, 10 g of a gumarabic sample (sample 1, sample 1/24, sample 1/48) was dissolved in 90 gof water, giving a 10 weight % gum arabic aqueous solution. In the samemanner, 20 weight % and 30 weight % gum arabic aqueous solutions wereprepared. Each aqueous solution was placed in a 100 mL screw cap vial,and the viscosities (mPa·S) were measured using a B-type rotationalviscometer (BM type, manufactured by TOKIMEC INC., rotor No. 1 with 60rpm), at 20° C. Table 2 shows the results. TABLE 2 viscosity (mPa · S)10% aqueous 20% aqueous 30% aqueous Sample solution solution solutionSample 1 11 40 192 Sample 1/24 12 45 240 Sample 1/48 13 57 300

Note that, although this depends somewhat on the products, a viscosityof 300 mPa·S is typical of gum syrups and corn soups, and is arelatively low viscosity.

As is clear from the results, the viscosities of the sample of themodified gum arabic of the present invention (Sample 1/24 and Sample1/48) were higher than that of the unmodified gum arabic (Sample 1).This increase in the viscosity affects the transfer of foodstuffs fromthe stomach to small intestine. When absorption of various nutrients andfood compositions is to be controlled, for example, the speed ofabsorbing glucose from the small intestine is reduced and theblood-sugar level rise is slowed down. It is believed that aninsulin-sparing action is thus achieved. Having a high viscosity isbelieved to affect the villus of the small intestine and to acceleratethe metabolism therein. Furthermore, it can prevent gastric ulcer byprotecting the stomach walls.

Example 1 Preparing Gum Arabic Powder

The modified gum arabic obtained in Experimental Example 1 can beprepared into a gum arabic powder by the following steps. Various kindsof foods and drinks as shown in Examples 2 to 4 can be prepared by usingsuch a gum arabic powder.

<Modified Gum Arabic Powder>

Modified gum arabic (Sample 1/24, 1000 g) was dissolved in 1500 g ofwater, giving a gum arabic aqueous solution. The aqueous solution wasspray dried using a spray drier (product of ANHYDRO, inlet at 140° C.and outlet at 80° C.), preparing 950 g of modified gum arabic powder.

Example 2 Fruit Juice Containing Soft Drinks (Brix 10°)

After mixing the following ingredients, the mixture was packed inbottles and sterilized at 85° C. for 30 minutes, preparing a soft drinkthat contained fruit juice. <Formula> High fructose corn syrup (Brix75°) 13.3 (weight %) Citric acid 0.1 Sodium citrate 0.05 Vitamin C 0.055-fold concentrated citrus fruits-containing 6.0 transparent juiceModified gum arabic powder (Example 1) 3.0 Water 77.5 Total 100.0(weight %)

Example 3 Hard Candies

<Formula> Sugar 59.0 (weight %) Glucose syrup 40.0 Water 20.0 Modifiedgum arabic powder (Example 1) 1.0 Citric acid 0.4 L-ascorbic acid 0.01Pineapple flavor 0.15 Total (after preparation) 100.0 (weight %)Sugar, glucose syrup and water were mixed, melted by heating to 155° C.,and cooled to 125° C. Modified gum arabic powder, citric acid,L-ascorbic acid and pineapple flavor were sequentially added to themixture, and formed into a desired shape, giving hard candies.

Example 4 Supplement (Pharmaceutical Preparation Containing DietaryFiber)

The following powdered ingredients were mixed, and supplements (tablets)were prepared using a tableting machine (tabletting pressure of 1 t).<Formula> Modified gum arabic powder (Example 1) 30 (weight %) Sorbitol69 Sucrose esters of fatty acids 1 Total 100 (weight %)

INDUSTRIAL APPLICABILITY

The modified gum arabic of the present invention is modified so as tocontain dietary fiber at a high content, such as a total dietary fibercontent of not less than 90 weight %. In recent years, many researchershave indicated that an insufficient dietary fiber intake is relevant tothe increase in patients suffering from diabetes, obesity,arteriosclerosis and the like lifestyle-induced diseases. Therefore, thephysiological functions of dietary fiber have been attracting attention,and the necessity of intaking dietary fiber has been highlighted. Themodified gum arabic of the present invention can increase the dietaryfiber content of foods or drinks by being added to foods or drinks as adietary fiber material or as an additive for enriching dietary fiber.This allows foods and drinks to have various physiological functions(e.g., reducing blood cholesterol levels, improving bowel movements,improving intestinal conditions, improving intestinal functions,controlling blood lipid levels, and controlling blood-sugar levels) oran effect of preventing the development of cancer. Furthermore, becauseof its physiological functions (e.g., reducing blood cholesterol levels,improving bowel movements, improving intestinal conditions, improvingintestinal functions, controlling blood lipid levels, and controllingblood-sugar levels) or an effect of preventing the development ofcancer, the modified gum arabic of the present invention can be used asa material for medicine having such effects. Furthermore, the modifiedgum arabic of the present invention has a low viscosity even at highconcentration. Therefore, the modified gum arabic of the presentinvention can be added to foods or drinks without adversely affectingtheir texture, making it possible to take a large amount of dietaryfiber.

The present invention provides foods and drinks having an increaseddietary fiber content by containing modified gum arabic terein. Bycontaining a large amount of dietary fiber, the foods and drinks of thepresent invention can be provided as health foods or functional foodshaving various physiological functions (e.g., reducing blood cholesterollevels, improving bowel movements, improving intestinal conditions,improving intestinal functions, controlling blood lipid levels, andcontrolling blood-sugar levels) or an effect of preventing thedevelopment of cancer due to the dietary fiber contained therein.Furthermore, the present invention can provide medicines having variousphysiological functions (e.g., reducing blood cholesterol levels,improving bowel movements, improving intestinal conditions, improvingintestinal functions, controlling blood lipid levels, and controllingblood-sugar levels) or an effect of preventing the development of cancerdue to the dietary fiber contained therein.

1. Water-soluble modified gum arabic having a total dietary fibercontent measured by the AOAC method of not less than 90%.
 2. Modifiedgum arabic according to claim 1, which has the weight-average molecularweight of not less than 1 million.
 3. Modified gum arabic according toclaim 1, which is used as a dietary fiber material for a food, drink, ormedicine.
 4. Modified gum arabic according to claim 1, which is used asan additive for enriching dietary fiber of a food, drink, or medicine.5. Modified gum arabic according to claim 1, which is obtained byheating unmodified gum arabic.
 6. Modified gum arabic according to claim5, which is obtained by heating unmodified gum arabic at 110° C. for notless than 24 hours, or under conditions by which similar effects can beobtained.
 7. Modified gum arabic according to claim 1, which is ofAcacia senegal origin.
 8. A method for preparing the modified gum arabicof claim 1, which comprises a step of heating unmodified gum arabic at110° C. for not less than 24 hours, or under conditions by which similareffects can be obtained.
 9. A dietary fiber material for a food, drink,or medicine, the dietary fiber material comprising or consisting of themodified gum arabic of claim
 1. 10. A method in which the modified gumarabic of claim 1 is used as a dietary fiber material for a food, drink,or medicine.
 11. An additive for enriching the dietary fiber for a food,drink, or medicine, the additive comprising or consisting of themodified gum arabic of claim
 1. 12. A method in which the modified gumarabic of claim 1 is used as an additive for enriching the dietary fiberof a food, drink, or medicine.
 13. A food, drink, or medicine containingthe modified gum arabic of claim 1 as a dietary fiber material.
 14. Afood or drink whose dietary fiber content is increased by containing themodified gum arabic of claim 1 as a dietary fiber material.
 15. Thefood, drink, or medicine according to claim 13, which is used forimproving bowel movements, improving intestinal functions, improvingintestinal conditions, preventing obesity, controlling blood lipidlevels, reducing blood cholesterol levels, controlling blood-sugarlevels or preventing the development of cancer.
 16. A method forincreasing the dietary fiber content of a food or drink by adding themodified gum arabic of claim 1 as a dietary fiber material in preparingthe food or drink.
 17. Use of the modified gum arabic of claim 1 as adietary fiber material.
 18. Use of the modified gum arabic of claim 1 asan additive for enriching dietary fiber.
 19. Use of the modified gumarabic of claim 1 in preparing a food, drink, or medicine.
 20. Use ofthe modified gum arabic according to claim 19, wherein the food, drink,or medicine is used for improving bowel movements, improving intestinalfunctions, improving intestinal conditions, preventing obesity,controlling blood lipid levels, reducing blood cholesterol levels,controlling blood-sugar levels, or preventing the development of cancer.